/*
 *
 * Copyright (c) 2006-2011 Sam Collett (http://www.texotela.co.uk)
 * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)
 * and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses.
 * 
 * Version 1.3
 * Demo: http://www.texotela.co.uk/code/jquery/numeric/
 *
 */
(function($) {
  /*
 * Allows only valid characters to be entered into input boxes.
 * Note: fixes value when pasting via Ctrl+V, but not when using the mouse to paste
  *      side-effect: Ctrl+A does not work, though you can still use the mouse to select (or double-click to select all)
 *
 * @name     numeric
 * @param    config      { decimal : "." , negative : true }
 * @param    callback     A function that runs if the number is not valid (fires onblur)
 * @author   Sam Collett (http://www.texotela.co.uk)
 * @example  $(".numeric").numeric();
 * @example  $(".numeric").numeric(","); // use , as separater
 * @example  $(".numeric").numeric({ decimal : "," }); // use , as separator
 * @example  $(".numeric").numeric({ negative : false }); // do not allow negative values
 * @example  $(".numeric").numeric(null, callback); // use default values, pass on the 'callback' function
 *
 */
  $.fn.numeric = function(config, callback)
  {
    if(typeof config === 'boolean')
    {
      config = {
        decimal: config
      };
    }
    config = config || {};
    // if config.negative undefined, set to true (default is to allow negative numbers)
    if(typeof config.negative == "undefined") config.negative = true;
    // set decimal point
    var decimal = (config.decimal === false) ? "" : config.decimal || ".";
    // allow negatives
    var negative = (config.negative === true) ? true : false;
    // callback function
    callback = (typeof callback == "function") ? callback : function(){};
    // set data and methods
    return this.data("numeric.decimal", decimal).data("numeric.negative", negative).data("numeric.callback", callback).keypress($.fn.numeric.keypress).keyup($.fn.numeric.keyup).blur($.fn.numeric.blur);
  }

  $.fn.numeric.keypress = function(e)
  {
    // get decimal character and determine if negatives are allowed
    var decimal = $.data(this, "numeric.decimal");
    var negative = $.data(this, "numeric.negative");
    // get the key that was pressed
    var key = e.charCode ? e.charCode : e.keyCode ? e.keyCode : 0;
    // allow enter/return key (only when in an input box)
    if(key == 13 && this.nodeName.toLowerCase() == "input")
    {
      return true;
    }
    else if(key == 13)
    {
      return false;
    }
    var allow = false;
    // allow Ctrl+A
    if((e.ctrlKey && key == 97 /* firefox */) || (e.ctrlKey && key == 65) /* opera */) return true;
    // allow Ctrl+X (cut)
    if((e.ctrlKey && key == 120 /* firefox */) || (e.ctrlKey && key == 88) /* opera */) return true;
    // allow Ctrl+C (copy)
    if((e.ctrlKey && key == 99 /* firefox */) || (e.ctrlKey && key == 67) /* opera */) return true;
    // allow Ctrl+Z (undo)
    if((e.ctrlKey && key == 122 /* firefox */) || (e.ctrlKey && key == 90) /* opera */) return true;
    // allow or deny Ctrl+V (paste), Shift+Ins
    if((e.ctrlKey && key == 118 /* firefox */) || (e.ctrlKey && key == 86) /* opera */
      || (e.shiftKey && key == 45)) return true;
    // if a number was not pressed
    if(key < 48 || key > 57)
    {
      /* '-' only allowed at start and if negative numbers allowed */
      if(this.value.indexOf("-") != 0 && negative && key == 45 && 
        (this.value.length == 0 || ($.fn.getSelectionStart(this)) == 0)) return true;
      /* only one decimal separator allowed */
      if(decimal && key == decimal.charCodeAt(0) && this.value.indexOf(decimal) != -1)
      {
        allow = false;
      }
      // check for other keys that have special purposes
      if(
        key != 8 /* backspace */ &&
        key != 9 /* tab */ &&
        key != 13 /* enter */ &&
        key != 35 /* end */ &&
        key != 36 /* home */ &&
        key != 37 /* left */ &&
        key != 39 /* right */ &&
        key != 46 /* del */
        )
        {
        allow = false;
      }
      else
      {
        // for detecting special keys (listed above)
        // IE does not support 'charCode' and ignores them in keypress anyway
        if(typeof e.charCode != "undefined")
        {
          // special keys have 'keyCode' and 'which' the same (e.g. backspace)
          if(e.keyCode == e.which && e.which != 0)
          {
            allow = true;
            // . and delete share the same code, don't allow.
            // (will be set to true later if it is the decimal point)
            if(e.which == 46) allow = false;
          }
          // or keyCode != 0 and 'charCode'/'which' = 0
          else if(e.keyCode != 0 && e.charCode == 0 && e.which == 0)
          {
            allow = true;
          }
        }
      }
      // if key pressed is the decimal and it is not already in the field
      if(decimal && key == decimal.charCodeAt(0))
      {
        if(this.value.indexOf(decimal) == -1)
        {
          allow = true;
        }
        else
        {
          allow = false;
        }
      }
    }
    else
    {
      allow = true;
    }
    return allow;
  }

  $.fn.numeric.keyup = function(e)
  {
    var val = this.value;
    if(val.length > 0)
    {
      // get carat (cursor) position
      var carat = $.fn.getSelectionStart(this);
      // get decimal character and determine if negatives are allowed
      var decimal = $.data(this, "numeric.decimal");
      var negative = $.data(this, "numeric.negative");
		
      // prepend a 0 if necessary
      if(decimal != "")
      {
        // find decimal point
        var dot = val.indexOf(decimal);
        // if dot at start, add 0 before
        if(dot == 0)
        {
          this.value = "0" + val;
        }
        // if dot at position 1, check if there is a - symbol before it
        if(dot == 1 && val.charAt(0) == "-")
        {
          this.value = "-0" + val.substring(1);
        }
        val = this.value;
      }
		
      // if pasted in, only allow the following characters
      var validChars = [0,1,2,3,4,5,6,7,8,9,'-',decimal];
      // get length of the value (to loop through)
      var length = val.length;
      // loop backwards (to prevent going out of bounds)
      for(var i = length - 1; i >= 0; i--)
      {
        var ch = val.charAt(i);
        // remove '-' if it is in the wrong place
        if(i != 0 && ch == "-")
        {
          val = val.substring(0, i) + val.substring(i + 1);
        }
        // remove character if it is at the start
        // a '-' and negatives aren't allowed
        else if(i == 0 && !negative && ch == "-")
        {
          val = val.substring(1);
        }
        var validChar = false;
        // loop through validChars
        for(var j = 0; j < validChars.length; j++)
        {
          // if it is valid, break out the loop
          if(ch == validChars[j])
          {
            validChar = true;
            break;
          }
        }
        // if not a valid character, or a space, remove
        if(!validChar || ch == " ")
        {
          val = val.substring(0, i) + val.substring(i + 1);
        }
      }
      // remove extra decimal characters
      var firstDecimal = val.indexOf(decimal);
      if(firstDecimal > 0)
      {
        for(var i = length - 1; i > firstDecimal; i--)
        {
          var ch = val.charAt(i);
          // remove decimal character
          if(ch == decimal)
          {
            val = val.substring(0, i) + val.substring(i + 1);
          }
        }
      }
      // set the value and prevent the cursor moving to the end
      this.value = val;
      $.fn.setSelection(this, carat);
    }
  }

  $.fn.numeric.blur = function()
  {
    var decimal = $.data(this, "numeric.decimal");
    var callback = $.data(this, "numeric.callback");
    var val = this.value;
    if(val != "")
    {
      var re = new RegExp("^\\d+$|\\d*" + decimal + "\\d+");
      if(!re.exec(val))
      {
        callback.apply(this);
      }
    }
  }

  $.fn.removeNumeric = function()
  {
    return this.data("numeric.decimal", null).data("numeric.negative", null).data("numeric.callback", null).unbind("keypress", $.fn.numeric.keypress).unbind("blur", $.fn.numeric.blur);
  }

  // Based on code from http://javascript.nwbox.com/cursor_position/
  // (Diego Perini <dperini@nwbox.com>)
  $.fn.getSelectionStart = function(o)
  {
    if (o.createTextRange)
    {
      var r = document.selection.createRange().duplicate();
      r.moveEnd('character', o.value.length);
      if (r.text == '') return o.value.length;
      return o.value.lastIndexOf(r.text);
    } else return o.selectionStart;
  }

  // set the selection
  // o is the object (input)
  // p is the position ([start, end] or just start)
  $.fn.setSelection = function(o, p)
  {
    // if p is number, start and end are the same
    if(typeof p == "number") p = [p, p];
    // only set if p is an array of length 2
    if(p && p.constructor == Array && p.length == 2)
    {
      if (o.createTextRange)
      {
        var r = o.createTextRange();
        r.collapse(true);
        r.moveStart('character', p[0]);
        r.moveEnd('character', p[1]);
        r.select();
      }
      else if(o.setSelectionRange)
      {
        o.focus();
        o.setSelectionRange(p[0], p[1]);
      }
    }
  }

})(jQuery);